Immuno-competence is recognized as an important factor in health and disease, particularly in cancer, its diagnosis, therapy and cure. A count of the circulating T, B and null cell lymphocytes per cc of blood is believed to provide a clue to a patient's immune status. It is proposed to develop a relatively fast and convenient method to identify and count T and B (and null) cells from peripheral blood samples and to use this ability to obtain clinical correlations of T and B cell counts for cancer patients undergoing radiotherapy. This is a collaborative effort of two laboratories in the Tufts-New England Medical Center's Radiation Oncology Center; viz. the radiobiology laboratory with extensive experience, and facilities in lymphocyte membrane and topology research, and the image processing laboratory with similar wide capabilities making quantitative computer-aided analyses of cell images, particularly of leukocytes. T, B and null cells, tagged by immunological methods (erythrocyte rosettes and/or immunofluorescence) will be analyzed quantitatively, after fixing and staining by one or more of several image measuring methods. Cells will be partitioned into nucleus and cytoplasm. Parameters describing each of these components will be computed, and those best able to differentiate between cell types will be selected. Methods developed previously by us will be adapted for this work. When a successful method is found, it will be used to examine selected groups of patients. T, B and null cell counts will be obtained before, during and after different degrees of immunosuppressive therapy. Correlations will then be examined between the cell counts and the clinical and treatment data which will have been recorded in depth.